Coronary heart disease is the most frequent disease of industrialized nations and for more than a hundred years their most frequent cause of death, by far. The community incurs enormous harm through these illnesses, both through the loss of human lives as well as due to the surgical treatment costs of heart patients.
One cause of heart disease is arteriosclerosis of the coronary arteries, which leads to insufficient blood circulation in various areas of the heart musculature. This can lead to heart trouble and a risk of ischemia. In serious cases, an acute occlusion of a coronary artery can lead to irreversible damage of the myocardial tissue, including myocardial infarction and a risk of death.
Previously, a number of solutions for the treatment of coronary artery disease have been developed. In less serious cases, it is frequently sufficient to treat only the symptoms with drugs or the underlying cause of the disease with a change of lifestyle. In the former cases, the coronary occlusion can be treated intravascularly or percutaneously with methods like balloon angioplasty, atherectomy, laser ablation, stents, and suchlike.
However, even these methods of treatment reach their limits and, in general nowadays, a so-called bypass is added if all or the majority of the coronary vessels, are profoundly constricted or are closed and the above-listed alternative methods of treatment fail. In doing so, a connection for the blood stream is created so that a blocked or stenotic or extremely narrow section of a coronary artery is circumvented. More precisely, in a bypass procedure the blood stream to an occluded or blocked target vessel is restored by connecting a source of oxygen-containing or arterial blood with a section of an artery or vein.
In this procedure, the target coronary artery can be any of the coronary arteries arranged around the surface of the myocardium, which supply the heart tissue with blood. Belonging thereto are the right and left coronary artery on the anterior surface of the heart. Often vein segments from the patient's own body serve as the bypass, which were previously removed from the upper and lower leg of the patient. The vein segment is sutured into the coronary arteries distal, or downstream of the bottleneck, with fine sutures, and thereafter directly into the aorta. Alternatively, a rear thoracic wall artery can (i.e. the left arteria mammaria interna (LIMA)) be applied as the bypass. With this blood vessel, the suture is only made distal to the narrowing in the coronary artery. The natural inflow from an anabranch of the aorta is retained, whereas the thoracic wall continues to be supplied by alternative blood vessels thereafter.
The attachment of a blood vessel to another is generally characterized as “anastomosis”, for example, the attachment of a graft or a mobilized aorta (e.g. LIMA) to the coronary artery. Normally, the blood vessels are sutured together by the surgeons to create an anastomosis. When using a free graft vessel, an end of the transplant vessel is sutured to an exit artery, such as the aorta, and the other end of the graft is sutured to a target coronary artery, as in the left anterior descending (LAD), which supplies the heart musculature with blood. If a pedunculated or peduncle graft, like the left internal thoracic artery (LIMA), is used for the bypass, the surgeon cuts the LIMA free and attaches the loose end of the LIMA directly to a target coronary artery with sutures. Due to the small proportions (2-5 mm), the stitching of the LIMA to the coronary artery of the heart requires that the treating surgeon is very meticulous. For this purpose, the surgeon uses a magnifying glass with a light source placed on his or her head.
Just a few years ago, bypass operations generally required the opening of the thoracic wall through median sternotomy, the spreading apart of the left and right thoracic wall and the opening of the pericardium, in order to have direct access to the heart. A cardio-pulmonary bypass is normally performed, so that the beating of the heart can be stopped during surgical intervention. This normally requires arterial and venous cannulation, a connection of the bloodstream with a heart-lung machine, cooling of the body to approximately 32° C., aortic cross-clamping, and a cardioplegic perfusion of the coronary arteries to immobilize the heart and cool it down to around approximately 4° C. The complete immobilization or arrest of the heart is generally necessary, as the constant pumping movement of the beating heart would make the operation on the heart difficult at certain times, and at other times, extremely difficult, if not impossible.
When a standstill of the heart has been achieved, the above-mentioned vascular bypass is surgically attached. At the end of the operation, the heart and lungs of the patient are reconnected to their vascular systems, the heart is restarted, and the heart-lung machine is disconnected. Thereafter, the cannula is removed and, finally, the thoracic wall is closed again.
In general, these bypass operations are complex and cost-intensive.
The use of the cardio-pulmonary bypass is often accompanied by difficulties for the patient and increases the costs and the time that is necessary for the procedure. For a cardio-pulmonary bypass, the entire blood of the patient, which normally flows back into the right atrium, is redirected into a system which supplies the blood with oxygen, leads carbon dioxide away, and returns the blood to the aorta of the patient with sufficient pressure for further dissemination into the body. Generally, such a system requires multiple distinct components, including an oxygenator, multiple pumps, a reservoir, a blood temperature regulation system, filters, as well as flow rate, pressure and temperature sensors.
In addition, the contact of the entire blood supply, with which the use of the heart-lung machine is connected, is associated with massive trauma, potential kidney failure, clotting problems, sepsis, heart failure, septal hypokinesia, cerebral perfusion defect, and/or changes in personality, amongst other things, or in the worst case, death.
Furthermore, it can lead to circulatory shock if the heart does not readapt to its original activity after the heart-lung machine is switched off.
In addition, the above-named bypass procedures can not be performed on patients with serious accompanying diseases. Because it is normally necessary to clamp the aorta, deposits are torn free of the vascular wall as embolic material, upon the loosening of the aortic cross-clamp, i.e. the aorta has massive calcifications and scales. An aortic cross-clamp is an instrument for clamping the aorta, so that the heart-lung machine can take over the work completely. If the aorta is calcified in the area of this clamp, plaque can be washed away. As soon as this tissue detritus or other particles have reached the circulation, they can clog other blood vessels and cause an embolism, for which an acute life-threatening complication arises. Embolisms with stroke and perfusion defects in internal organs thus lead to death in a major percentage of bypass patients, even post-operatively after a few days.
Due to the risks that arise during a cardio-pulmonary bypass, man has attempted to perform coronary artery bypass procedures without stopping the heart and without a cardio-pulmonary bypass. Thus many percutaneous and also surgical heart bypass procedures have been developed, which are performed by openings in the intercostal space, as for instance disclosed in U.S. Pat. No. 6,167,889 to Benetti, and U.S. Pat. No. 6,332,468 to Benetti. However, these approaches are still quite invasive.
In addition, bypass and other surgical procedures performed on beating hearts are finding increasingly greater application. However, the need for improved devices continues to exist, which simplify the performance of these procedures and reduce the invasiveness further. The minimally invasive direct coronary bypass (MIDCAB) revascularization with the arteria mammaria (LIMA) to the intraventricular artery (LAD) has established itself in the method as a clinical procedure for a portion of the patients.
For procedures on beating hearts, it depends particularly upon maintaining the hemodynamic function of the heart during the procedure, as required. For example, it has been demonstrated that the manipulation of the heart during a procedure leads to the deterioration of its hemodynamic function, which in some cases can have dramatic, seriously life-threatening consequences for the patient.
In a revascularization (restoration of the blood circulation) on a beating heart by means of a mini-thoracotomy (small thoracic wall opening), the access trauma can be reduced and the use of the heart-lung machine can be done without. However, from a medical point of view, the results are not yet satisfactory, so that the previously named accepted surgical methods can be done without, as a rule.
Recently, the first clinical efforts were made to perform the revascularization of the LAD on a beating heart completely endoscopically and with robotic support. Even in this method, the anastomosis is performed conventionally with surgical suture methodology and, thus, represents a substantial technical challenge which prevents broad application. Even the results of the robotically supported suturing methods are in no way satisfactory from a medical point of view.
Furthermore, it is well known that heart surgeries always become more challenging due to the increasing aging and multimorbidity of the population, and the increasingly scarce working hours of the surgeons. Overall, the entire field is leading to a financially increasing burden on public health.
In Germany alone, for approximately one hundred thousand bypass procedures, several hundred thousand coronary anastomoses are performed by surgeons. The cost for this procedure today equals at least $27,000 per patient. Previously, the procedure is associated with a substantial mortality rate (2-15% depending on patient population, procedure, re-intervention, etc.).
It is therefore preferable to perform a bypass operation without a heart-lung machine with a beating heart, and without involvement of the central blood vessels.
Thus, there is a need for an improved system and method for cardiac access and bypass procedures.
Hence, an improved system and method for cardiac access and vessel access, for instance for facilitating bypass procedures, would be advantageous, and in particular, a system, method or device allowing for increased flexibility, cost-effectiveness, patient comfort, patient safety, and independence of heart-lung machines or minimized invasiveness.